Reversing-furnace mechanism



June '3, 1924.- 1,496,520

C. L. BYRON REVERSING FURNACE MECHANISM Filed Aug. l2 1920 4 Sheets-Sheet 2 fide/ZW f Patented dune 3, 1924..

Lggz@ errantes L. nvnon, or winnnrna, ILLiNoIs, Assrenoe 'ro stances c. s'rnnsn, or BUFFALO; new Yoan.

EEVERSINC -FUBJNACE IKECHANISM.

To cZZ whom t ml/ concern:

Be it known that I. @Hannes L. BYRON, a citizen of the United States, residing at VVinnetka, in the county of Cook and State of Illinois, have invented certain new and,V useful Improvements in Reversing-Furnace Mechanism, of which the following is a specification.

This invention relates to a reversible furnace mechanism, and is an improvement on the arrangement disclosed in a copending application, Serial No; 396,437, filed July 15, 1920, in the name of Marcus C. Steese. I disclaim the invention disclosed in said Steese application. l

One object of this invention is to improve the control of reversible furnace mechanism in a manner to, eliminate the personal element of error in the opera-tion of the furnace.

Another Objectis to vprovide a control arrangement for reversing the furnace, controlling the flow of gas and air, and purg ing the furnace of all combustible gas ber fore reversal, in a given sequence, and 1n a manner to prevent explosions which heretofore have ruined many furnaces and apparatus associated therewith.

Another object is to provide reversible furnace control mechanism adapted to meet the various requirements for successful commercial operation. A

These and other objects are accomplished by means of the' arrangements disclosed on the accompanying' sheets of drawings, in which- Figures 1 to 5, inclusive, show somewhat diagrammatically and schematically an arrangement of` valves for a. reversible onen hearth furnace, and means for controlling the same to accomplish the desired results, the valves in the various figures being shown indifferent positions to effect the proper operation of the furnace in reversing the same. The significance of the positions of the various valves and controlled parts in the diiferent figures of the drawings will be particularly referred to throughout the specification;

yFigures 6 and 7 are top plan views of two associated slotted disks forming parts of the control or interlock mechanism;

Figure 8 is a fragmentary detail plan view of the operative connection between a gas reversing valve and a gas shut-off valve Application filed Augusty 12, 1920.` Serial No. 403,054.

at one end of the furnace, said connection including a purge valve interconnected with, and movement of which is controlled by, said associated gas reversing and gas shut-off valves and their interlocking mechanism Figure 9 is a fragmentary front, elevation of the same arrangement;

Figures 10 and 11 are views taken on the lines 10-410 and 11%1'1`o-f Figure 9;

Figure 12 is a view similar to that shown in Figure 4, but showing a modified form of interlock or control mechanism between various valves; Y

Figure13 is a perspective view of said iuodified form of control means or inter-V lock; and v, y

Figure 14 is a top plan view ofthe same control and interlock mechanism.

The various novel features of the inven-v tion willbe apparent from the. following description and drawings and lwill be particularly pointed out in the appended claims. Y

The purging of a reversible furnace, such as an open hearth furnace, for example, is a matter of great and increasing importance,

vnot only for the purpose of preventing'eX- plosions which ruin furnaces and associated apparatus, such as boilers which use waste heat from the furnaces. but also for preventing the waste of gas, which is expensive. These reversible furnaces are reversed quite frequently, in some instances every fteen minutes. In "ordinary practice, however, where the furnaces are reversed every half hour. the loss caused by the waste of gas upon reversal mounts to five percent of the amount of fuel consumed. By purging, and controlling the purging of the furnace in the manner to be fully considered herein, no gas is wasted upon reversal; but, on the other hand, all gas passing from the gas supply means to the various parts of the furnace, including its uptakes, etc., is efficiently consumed before reversal of the furnace. Furthermore, the whole interrelated control mechanism, including the purge control, is arranged to insure economic and safe-operation.

In Figures 1 to 5, inclusive, and Figure 12,`an open hearth furnace 10 is shown having tivo operative ends No. 1 and No. 2. The No. 1 end of the furnace is provided with an air chamber 1l. and gas chamber 12,- and ics.

the No. 2 end of the furnace similarly is provided with an air chamber 13and a gas chamber 14. Air is supplied to the air chamber 11 through an air lid 15 and through a connecting passageway 16 -when the air reversing valve 17 is removed from the air valve seat 18. The gas is supplied to the gas chamber 12 through passageway 21 from a gas supply main 19 when the gas shut-ofi' valve 20 is in open position, the gas reversing valve 22 being in closed position when its associated gas shut-oil' valve is open. As shown in Figures 1 and 2, the air reversing .valve 17 and the gas reversing valve 22 Acover the stack connections 23 and 24, respectively.

In connection .with No. 2rend of thefurnace, air is supplied through an air lid 25 and passageway 26 when the air reversing valve 27 is removed from its valve seat 28.

Gas is supplied to the gas chamber 14 from aY gas supply mainf29 through a gas passageway 30 when the gas shut-ofi' valve 31 is open and the associated gas reversing valve 32 is closed. The gas reversing valve 32 controls the flow of the products of combustion passing outwardly from the gas chamber 14 tothe stack connection 33, and the air reversing valve 27 also controls the passage of products of combustion passing outwardly of the air chamber 13 to the stack connections 34 when gas is supplied from the opposite end of the furnace. The gas shut-olf valves 20 and 31 are controlledby levers 35 and 36, respectively, pivotallyl supported at points 37 and 38. respectively, the limits of outward movement of said levers 35 and 36 being controlled by stop members 39 and 40, respectively. The levers 35 and 36 cooperate with a disk 41 in a manner to be ,considered in detail hereinbelow. A. single lever 42 is provided. for controlling the operation ofair reversing valves 17 and '27, said lever being connected tosaid valves. respectively. by flexible members 43 and 44 which pass through sheaves 45 and 46, respectively. A single lever 47 operates and controls the gas reversing valves 22 and 32, respectively. said lever being connected to the valves 22 and 32, respectively, by flexible members 48 and 49, respectively. which pass over sheaves 50 and 51, respectively.

Thus far, in connection with the valve mechanism, attention has been called only to the air reversing valves, gas reversing valves, and gas shut-ofil valves. In addition to these valves, there is provided a purge valve at each end of the furnace whereby the entire system of the furnace may be purged of all combustible gas'coming from either gas main 19, at one end of the furnace, or gas main 29, at the other end, prior to reversing the furnace. Not only is it of great value to provide purge lvalves for accomplishing the above-mentioned result,

but also it is of a prime importance that the purging action should take place at a definite relative time and just prior to the reversal of a supply of air and gas tothe furnace. To properly time and coordinate the purging action with the shut-oft' of the gas and reversing of the furnace, there is provided an interlocking connection between the gas reversing valves and the gas shutoli valve for each end of the furnace, said interlocking connection in -each case including .a purge valve, each ofwhich under .certain conditions' is actuated in, accordance with separate movements of the associated gas reversing valves and gas shut-off valve; for instance, the purge valve 52 at No. 1 end of the furnace under given conditions is responsive to movements of the associated gas reversing valve 22 and the gas shut-off valve 20. Likewise, the purge valve 53 at No. 2 end of the furnace under given conditions is responsive to movements of the associated gas reversing valve 32 and the gas shutoif valve 31. The Vconnection between the gas reversing valve and gas shut-off valve, including the associated purge valve, comprises a plurality of associated leversshown in detail in Figures 8 to 11 inclusive. The arrangement shown in said figures is the-one applied to the No. 2- end of the furnace, but it will be understood that the lever arrangement at No. 1 end of the furnace Aacts inthe same manner. The same reference characters which are applied to the interlock between the gas shut-olf valve 31 and gas reversing valve 32 at'No. 2 end of the furnace will be used, but primed in connection with the corresponding interlock at No. V1 end of the furnace.

ln the arrangement shown in Figures 8 to 11, inclusive, there are two levers 54 and 55, an intermediate portion of the former being connected to one end of the latter by a link 515. Lever 55 is pivotally connected at 57 to any suitable support, and lever 54 in eect is a floating lever suspended from lever 55 by the link 56. Y end of the lever 54 is the purge lvalve 53, the stem of the latter being guided between suitable guides 58. The opposite end of the lever 54 is operated between a stop member 59 at the lower side of the lever and a projection 60 at the upper side of the lever and carried on the stem of gas shutoff valve 31. The upper side of the free end of the lever 55 is operated upon by a projection 61 carried by the stem of gas reversing valve 32.

.is shown in Figure l of the drawings, gas shut-ofi valve 31 is closed, gas reversing valve 32 is open. and purge valve 53Wis closed, the free end of lever 54 resting upon its stop 59. In Figure 4, it will be noted that the gas reversing valve 32 has been lowered, its projection 61 passing into engagement with the free end of lever 55 and Hung from one` (lll lill) llO causing thev purge valve 53 to be opened through the action of levers 55 and 54, the latter tulcruming above its stop member 59. Tith the parts in the position shown in Figure 4, the gas shut-off valve 31 may be raised into the position shown in Figure 5. During the first part of the opening movement or the gas shut-oli valve 31 the purge valve 53 closes as a result of its own weight, the lever 54 pivoting about its point of pivotal connection 62 with the link 56, the tree end ot the lever 54 rising from stop member 5S) under the infiuence of the weight of the purge valve and .overlying projection ot g s shut-off valve 3l until the purge valve is seated, whereupon further opening movement ol the gas shut-off valve 31 is not accompanied b v a movement of the purge valve 53, lith the, parts in the position shown in Figure 5, the gas shut-off valve 31 may be closed, whereupon the purge valve 53 will be opened because of the projection 6ll of the gas shut-oii valve 31 passing into engagement with the upper side of the lever 54. for lifting` the purge valve 53 into open position, as shown in Figure 4. With the parts in such position, an opening ot the gas reversing valve 32 will permit Vthe purge valve 53 to move into closed position, as shown in Figure 1v` the weight of the released purge valve causing the closing, movement, the weij it ot the purge valve acting through lever 4, then tulcrumed against its stop member 59, through link 56 and lever 55. the free end of the latter rising with the vprojection 61 on the gas reversingl valve 32 until the purge valve 53 is seated, 'further opening movement of the gas reversing valve 32 being unaccompanied by any further movement ol3 the purge valve. Such is the ari-tion and control of the purge valve and parts thus far described.

The purge valve connection forms one selectivel)7 interlocking connection between the gas shut-off valve and the gas reversing valve. Another interlock is formed between the gas shut-olf valve and gas reversing valve taking the `form, in the instance shown in Figures 1 to 5, inclusive, of' a. plurality ot disks 41 and 63 serured to a revolubly mounted shaft, the gas shut-oli control levers35 and 36 cooperating with one oit the disks 4l and lever rentrolling the air reversing valves, and lever 47 controlling the gas reversing valves cooperatingwith the other disk 63.- Disk 41 (see Figures 2, 5

and 6) is provided with a radial slot 65 Jfor receiving each of the gas shut-ott control Ylevers 35 and 36 at, different times. It will be noted, as shown in Figure 2, that the gas shut-oil?` lever 35 has been permitted to enter and occupies the slot 65 for opening the gas shut-oil` valve 20 for permitting the flow of gas from the gas mainv 19. It also will be observed that the other lever 36 controlling the gas shut-oil' valve 31 s held in a position preventing an opening movement of the gas shuto'i valve Reterring to Figure 5, it will be noted that reverse conditions are true. shut-oli1 valve 31 has been moved into the disk slot 65 for opening the gas shut-off valve 31, and the other lever controlling gas shut-off valve- 2O is prevented from giving the gas shut-o valve 20 an opening movement. It is seen, therefore, that the arrangen'ient of disk 4l in the manner disclosed, among other things forms an interlock between the gas shut-oli1 valves -20 and 31 for opposite ends oi the furnace, it being impossible to open more than one gas shutoil valve at a time.

Referring to Figures 3, 4, 5 and 7, it will be seen that the other disk 63 is provided with a radial slot 66 tor the reception of the levers 42 and 47 which control the air reversing and gas reversing valves. Associated with the slot 66 is a spring-pressed dog 6'? pivotally mounted at 68 on the disk 69. a guided operating rod 69 being pro-l vided t'or the dog 67 for transmitting a-closing movement to the dog, asfshown in dotted lines in Figure T, in opposition to a spring 76 anchored to the disk at 71. The outer end o't the rod 69 is provided with a projection 72 which is` engaged by a. projection T3 at the lower end ot the lever 36 which controls one of the gas shut-off valves 31, the object being to lock the levers 42 and 4T within the slot to prevent a reversing movement of the gas and air reversing valves when the gas shut-ofi' valve 31 is in an open position, as shown in Figure 5 of the drawings. owever, as soon as the gas shutlo valve is closed, bvmoving the lever 36 out oi the slot 65 of disk 41, the dog 67 is drawn rearward/l5T- by spring 71 for permitting the levers 42 and 47 controlling the air and gas reversing valves to be moved out ot the slot 66 of disk 63 for reversing the air and gas reversing` valves. In view of the itact that each disk 41 and 63 has but a single slot and both are secured to the operating shaflt 64, is apparent that when the upper disk 41 presents its slot 65 to the lever 35 et the gas shut-off valve 20, the slot 66 in the lower disk 63 will not be presented to the levers 42 and 47 cont-rolling the air and gas reversing valves, andthat said levers will beheld in a position preventine' the reversal of the gas and air reversing valves.

It will be seen Ytrom Figure 2 of the drawings that in order to reverse the positions of thel air and gas reversing valves, first it will be necessarv to move the lever 35 out of the slot 65 oil disk 41 to close the gas shut-oit valve 2O before the shaft 63 and disks 41 andA 63 can'be rotatedto present-slot 66 of disk to the air and gas reversing val-ves 42 and Herein lever 36 controlling the gas 47 to permit a reversal of the air and gas reversing valves. In other words, when gas is being supplied from one end of the furnace from gas main 19, it is absolutely impossible for the gas and air reversing valves 22 and 17, respectively, to be raised from their stack connections and to lower gas and air reversing valves 32 and 37 to cover their stack connections: also when gas shut-ofi` valve 31 is in an open position to admit a supply of gas from gas main 29, as shown inFigure 5, it is impossible for gas and air reversing valves 32 and 27, respectively, to beraised from their stack connections and gas and air reversing valves 22 and 17 to be moved into a position covering their stack connections; that it is impossible for more than one gas shut-off valve to be open at a time, and that said gas shut-off valves and gas reversing valves must be operated in a given sequence. The purge valve connection forms one selectively interlocking connection between the gas shut-off valves and gas reversing va lves; and the shaft and disk arrangement forms a second interlock between said valves. Furthermore, the shaftr and disk arrangement, including disks 41 and A63, act as control means for the purge valves, as also do the gas shut-ofi'1 and gas reversing valves.

In the operation of open hearth furnaces, it takes almost two minutes to thoroughly purge the furnace and its variousparts, such as gas uptakes, etc., of all combustible gas after the supply of gas has been shut off. Also in the normal operation of open hearth furnaces, only about tive seconds are necessary to shut olf the supply of gas and reverse the furnace. Itis apparent, therefore,

that unless ysome special means is provided to prevent the reversal of the furnace for about two minutes after the gas has been shut Loff from the furnace, it will be impossible to thoroughly purge the furnace and itsupta'les of all combustible gas, the result being that the remaining` gas may mix with air in a manner to cause an explosion which will wreck the furnace and its associated apparatus. To prevent any such possibility and to cause the furnace to be thoroughly purged, I have provided means for preventing a reversal of the furnace until the gas shut-off valve has been closed for a certain predetermined time; for example, two minutes. This, means takes the form of driv-4 ing mechanism for the shaft 64 and the disks 41 and 63 secured thereto, and includes a shaft section 74 having a friction member 75 at one end frictionally engaging a disk 7 6 mounted at one end of shaft 64, shaft section 74 having secured thereto a relatively large gear 77 meshing with and driven by a ielatively smaller gear 78 secured to a shaft 7 9, to which also is secured a relatively large gear 80 which is driven by a relatively smaller gear 81 mounted upon a shaft S2 which may be driven by a motor 83 or clockwork or fan-retard mechanism. In other words, the shaft 64 will be driven relatively slowly through the reducing gear mentioned y in a manner whereby it will talte about two minutes to rotate the shaft G4 and its disks 41 andGS through 180o for permitting the reversal .of the furnace after the gas shutoff valve for one end of the furnace has been closed and the purge valve for said end of the furnace has been opened.

In connection with the complete cycle of operation of the furnace and its control mechanism, let it be assumed, rst, that the 31 at No. 2 end of the furnace. The purge valve 52 at No. 1 end of the furnace at this.

time is held in open position by the gas reversing valve 22. Upon opening the gas shut-off valve 2O (which is permitted at this time because disk slot 65 is in a position to receive the control lever 35 of the gas shut-off valve 20), for permitting the supply of gas over the gas reversing valve 22, the first few inches of motion permits the closing of the purge valve 52, whereupon any further opening movement of the shut-off valve 2() at No. 1 end has no effect upon the purge valve 52. The last part of the opening'movement of gas shutoft' valve 20, which does not affect the purge valve, is utilized in regulating the volume offiow of gas. The open gas shut-ot`f valve 20,with the closed purge valve 52, is shown in Figure 2 of the drawings, Gas being applied from the gas main 19 Hows past the closed purge valve 52 over the gas reversing valve 22 and in through gas chamber 12 to the gas port in the furnace (not shown). where it meets air which comes in from air lids 15 over the air reversing valve 17 at No. 1 end of the furnace, through the air chamber 11 and to the air ports of the furnace (not shown), there meeting and mixing with the gas. Combustion takes place in the furnace and the products of combustion pass outwardly from the furnace through the gas and air ports on the other or outgoing end. These waste gases which have passed out through the air port pass through air chamber 13 and to the air reversing valve 27, which is raised, sealing oft' the connection to the atmosphere through the air lids 25, said waste gases, therefore, passing underllO neath the air reversing valve 27 to the stack connection 34. The waste gases which pass out through the gas port at No. 2 end of the furnace pass through the gas chamber 14 and out below the gas reversing valve 32 to the stack connection 33. The gas shut-off valve 31 at No. 2 end of the furnace being closed and its associated purge valve 53 being closed, and both being locked in closed position by the interlock mechanism, including disks 41 and 63, there is no How of air, combustible gas or any other gas, from either` of said sources to the stack, thereby avoiding explosions occasioned by gas and air which otherwise might pass the gas shutoff valve 31 and purge valve 53 into the stack connection 33 which may lead to a waste heat boiler or any other associated apparatus.

lVith the parts in the positions described and as shown in Figure 2, it is impossible to reverse the furnace, or, in other words, to reverse the positions of the air reversing and gas reversing valves until the gas shutofi' valve 20 is closed, for the reason that the lever is in the disk slot 65, preventing a rotating movement of the disks 41 and 63, the levers 42 and 47 controlling said reversing valves being locked against a reversing movement because the slot 66 in disk 63 is not presented to said levers 42 and 47 and cannot be presented to said levers until the disk is rotated through 1300. In reversing the furnace the gas shut-off valve 20 on No. 1 end of the furnace is first closed, the first part of its closing movement not affecting the position of its associated purge valve 52. The last few inches of the down stroke of the gas shut-off valve 20, however, raises the purge valve 52, as shown in Figure 1 of the drawings. The gas being shut off', the purge valve is automatically opened to the atmosphere or to a supply of any other purging medium, such as products of combustion. At this point it may be stated that the temperature in the gas chamber and air chamber and the gas uptakes and the air uptakes, on all sides, creates a suction upon the gas and air reversing valves. This suction draws in through the purge valve the purging medium on No. 1 end of the furnace, which purging medium displaces the gas in the gas valve chamber and passageway 21, gas chamber 12, and in the gas uptakes leading to the intake ports of the furnace. This gas burns Vas it did when the supply of gas was furnished past the gas shutoff valve 20 on No. 1 end, `With the parts then in the position shown in Figure 1, the shaft 64 and its disks 41 and 63 may be rotated by the slow drive mechanism hereinabove referred to, which may be start# ed in Voperation by throwing in a switch or pressing a button, as is well understood. Within a given time, which is purely a mat ter of choice, such as two minutes, the disks may be moved through an' angle of 180", whereupon the slot 66 of disk 63 is presented to the control levers 42 and 47 for the air and gas reversing valves, whereupon said levers may be moved to the left for reversing the furnace. It will be understood that during the time the shaft 64 and its disks 41 and 63 are being rotated through 180", all of the combustible gas in the furnace and its uptakes has: been efiiciently burned within the furnace, eliminating the possibility of an explosion upon reversal of the furnace. Also it will be understood that after the shaft 64 and its disks 41 and 63 have been rotated through an angle of 1800, the motor or driving mechanism may be stopped, either by hand, by pulling a switch or pushinga button, or automati cally, or, if desired, the friction disks 75 and 76 may be moved out of operative engagement with each other or permitted to slip when no rotation of the disks 41 and 63 is desired.

The air reversing valves 17 and 27 and the gas reversing valves 22 and 32 are then permitted to be thrown over through an intermediate position, shown in Figure 3 of the drawings, by an operation of the levers 47 and 42. The first few inchesV of motion in throwing over the gas reversing valves close the purge valve 52 at No. 1 end of the furnace. It will be noted that the. purge valve 52 is closed before the gas reversing valve 22 opens the connection between the gas chamber 12 andthe stack connection 24 on No. 1 end of the furnace. The purge valve 53 on No. 2 end still isclosed and will not open until the gas reversing valve 32 for No. 2 end has entered the seal and cut off the connection from the gas chamber 14 to the stack connection 33 on that end. Continuing the reversing movement from the position shown in Figure 3, the last few inches of downward movement of the gas reversing valve 32 opens purge valve 53 on No. 2 end, this arrangement being shown in Figure 4 of the drawings. The opening of the purge valve 53 at this instant serves no function other than permitting an inspection of the associated gas shut-off valve to determine whether gas is leaking from the gas main 29. From Figures 3 and 4 it will be noted that just as soon as the air and gas reversing levers 42 and 47 are moved into slot 66 of disk 63', the disks 41 and 63 are locked against rotation with the gibs Shut- 'of valve 2O on No. 1 end of the furnace being prevented from being moved to an open position. After the furnace has been reversed, as shown in Figure 4 of the drawings, the furnace is ready to receive gas from No. 2 end, whereupon the operator opens the gas shut-QE valve 31 by a movement of lever 36 in a clockwise manner,

which. at this time is permitted because the disk slot 65 is inV a position to receive the lever 36, the parts then being arranged as shown in Figure 5. As the lever 36 is moved in a clockwise direction, the dog 67 on disk 63 is moved into a position to lock the air and gas reversing valve levers 42 and 47 within the disk to prevent a reversal of. the air and gas reversingr valves while the gas shut-off valve 31 is in open position, and accordingly prevents improper movenient of the purge valves. The first few inches of the opening movement of the gas shutoff rvalve 31 permits the purge valve 53 to close. The remaining opening movevment of the gas reversing valve 32 is unaccompanied by any further movement of t-he purge valve, said further opening movement of the gas reversing valve servin as means for regulating the quantity of ow of gas to the furnace. Gas from the No. 2 end supplied from gas main 29 flows past the closed purge valve 53 over the gas reversing valve 32 to the gas chamber 14 and then through the fines and uptakes to the gas port of the `openY hearth furnace, the stack connectionon No. 2 end being cut oQ by the. gas reversing valve 32. Air is admitted from the atmosphere through the air lids` 25,'on No. 2 end through the air chamber 13 and its corresponding flues and uptakes to the air port of the furnace, where the air and gas combine and combuston takes place. The waste gases pass outwardly from the furnace through the outgoing vair and gas ports'on No. 1 end down through the uptakes, through air chambers and gas charnbers to the stack connections 23 and 24 under the air and gas reversing valves 17 and 22, respectively, it being noted that the connection to the atmosphere for No. 1 end through the air lids is sealed off by the up per portion" of the air reversing valve 17. The gas shut-ofil valve 20and the purge valve '52 for No. 1 end being closed and locked in closed position through the interlocking mechanism, including disks 41 and G3, there is no connection between the stack and the gas main or between the stack and the atmosphere or any other source of gas to the stack through the gas reversing valve 22 on No. 1 end, thereby eliminating any danger of explosions.

Then ready to reverse the furnace from No. 2 end to No. 1 lend, the operator first closes the gas shut-off valve 31 on No. 2 end of the furnace, and, as described above` it impossible to reverse the furnace until this is done, the first part of the closing movement of the gas shut-off' valve 31 not affecting Vthe position of the associated purge valve 53, the llast few inches of the closing movement of the gas shut-off valve 31. however, raising or opening the associated purge valve 53, as shown in Figure 4 of the darw ings, whereupon the suction due to the hot gas chambers and the uptakes draws in through the purge valve 53 on No. 2 end of the furnace any suitable purging medium for displacingthe combustible gas in the gas chamber, flues and uptakes, such combustible gas being burned efficiently in the furnace. vWhen the lever 36 controlling the gas shut-ofil valve is moved in a counterclockwise direction from the position shown in Figure for closing the gas shut-off valve 31, as shown in Figure 4, the spring 70 on disk 63 is permitted to withdraw the dog GT to permit a reversal of' the furnace, whereupon the levers 42 and 47 will be moved to the right for reversing the furnace, the parts moving through positions indicated in Figures 3 and 2 to positions indicated in Figure 1` wherein in the meantime the disks 41 and 63 have been rotated 1S()o for locking the control levers 42 and 4T against a reversing movement and locking the gas shut-off valve 31 at No. 2 end of the furnace in closed position, and permitting the gas shut-ofi valve at No. 1 end of the furnace to be opened, as shown in Figure 2 of the drawings; it being understood that upon the reversal shown in Figure 1, purge valve 52 is first opened an instant for inspection purposes and then closed, as shown in Figure 2, when the gas shut-off valve 20 is open. A complete cycle in the regular operation of the furnace has now been described.

In Figures 12. 13 and 14, I have shown what l consider to be the preferred form of disk interlock mechanism between the various valves. 1n this arrangement l provide three disks instead of two, as shown in other figures of the drawings, and dispense with the use of the spring-pressed locking dog 67.

The arrangement of the valves shown in Figure 12 corresponds with the arrangement. shown in Figure 4 of the drawings. ln the interlock mechanism shown in Figures 12. 13 and 14, I have provided a shaft 8O which is driven from a shaft 31 through the timing or slow driving mechanism 32 described in connection with the other figures of the drawings, the operative connection between shafts and 81 being through frictional disks 83 and 34, respectively. The upper disk is associated with the control lever 3G for the gas shut-off valve 31 for No. 2 end of the furnace and control lever 87 for gas shut-off valve 2O for No. 1 end of the furnace. This disk 35 has a slot 38 for receiving said levers 86 and 37 at different times, at all times excluding the opposite oneof said levers for preventing the opening of its associated gas shut-off valve. This disk is also provided with a stop member 89 which at the proper times automatically1 resists movement of the shaft 30, disk and the other two disks 90 and 91, all of which macteo disks are rigidly secured to the shaft 80. The intermediate disk 90 and the lower disk 91 are associated with and control the operation of the levers 92 and 93, which in turn control the air reversing valves 17 and 34 and gas reversing valves 22 and 32, respectively. The levers 86 and 87 are pivoted at points 94 and 95 at their lower ends, respectively, while the levers 92 and 93 are pivoted at point 96 intermediate their ends.

As shown in Figures 12, 13 and 14, the air and gas reversing valves are in a position for gas to be supplied from No. 2 end of the furnace. However, as shown, the gas shutoif valve 31 at No. 2 end of the furnace cannot be opened until disk has been rotated a few degrees in a counterclockwise direction, as indicated by the arrow; or, in other words, until the stop projection 89 has moved into engagement with the gas control lever 86, when the slot 88 in disk 85 will be in a position to receive the lever 86. When the lever 86 is moved into the slot 88 the gas shut-oli` valve 31 is opened to supply gas from No. 2 end of the furnace. At this time the shaftV 8O and the disks 85, 90 and 91 will be locked against rotation; or, in other words, the gas shut-olf valve 2O will be locked in closed position, the air and gas reversing valves locked against a reversing` movement, and the purge valve 52 prevented from making any movement. `When it is de- .sired to reverse the valves, the gas control lever 86 is moved out of the slot 88 and temporarily against tension of spring 97 beyond the stop projection 89, whereupon the shaft 80 will be caused to rotate by the slow drive mechanism 82. After the gas lever 86 has been withdrawn from the slot 88 and beyond the stop 89, the shaft 80 and its disks will be permitted to rotate in a counterclockwise direction until the stop portion 97 of intermediate disk 90 passes into engagement with the gas control lever 93. At this time the levers 92 and 93 may be moved to reverse the position of the air and gas reversing valves, it being noted particularly from Figure 14 that the disks 90 and 91 are spaced f laterally with respect to each other to provide a passageway for the levers 92 and 93. From the time that the gas shut-olf lever has been moved out of the slot 88 and beyond the stop 89, and until the reversing levers 92 and 93 have been moved into a reverse position from that shown in Figure 13, the purge valve at No. 2 end of the furnace has been open for purging purposes, as fully discussed hereinabove. After the positions of levers 92 and 93 have been reversed from that shown in Figures 12 and 13, the shaft 80 and disks thereon are free to rotate further in the direction of the arrow; it being understood that the slot. 88 in disk 85 at the time of the reversal of levers 92 and 93 had not advanced suiciently and was not in aposition to receive the gas controllever 87. However, after the reversal of said levers 92 and 93 from the position shown in Figures 12 and 13, the disks are free to rotate a few degrees,

87 will be thrown into the slot for opening the gas shut-olf valve for supplying gas from No. 1 end of the furnace; it being understood that when the lever 87 is in the slot 88 the reversing valves 92 and 93 are prevented from making a reversing movement. To reverse the furnace again back into the position shown in Figures 12 and 13, it is first necessary to withdraw gas control lever 87 from the slot 88, whereupon after the shaft and disk have been rotated through a relatively largc angle at slow speed, during which purging action is taking` place, the air and gas reversing levers 92 and 93 may {inally be reversed into the Iposition shown in Figures 12 and 13 of the drawings. During about 170O of movement the reversing levers 92 and 93 ai'e prevented from reversing movement by engaging the edge of disk 91 which they ride, and during another 170o of movement in a reversed position, by' engaging the edge Yof disk 90 which they ride. These levers 92 and 93 preferably are normally releasably locked together by a removable link 98.

There may be various other modifications of the invention and it is my intention to Coverall such modifications which do not involve a departure from the spirit and scope of the following claims.

I claim: Y

1. ln reversing furnace mechanism, the combination of a gas shut-0E valve, a gas reversing valve, a purge valve controlled by said gas shut-off valve whereby the purging of the furnace of gas is controlled, and means whereby the furnace cannot be reversed before closing said gas shut-olf valve.

2. ln reversing furnace mechanism, the combination of a gas control valve, a reversing valve, a purge valve controlled by one of said valves whereby the purging of the furnace of gas is controlled, and means whereby the furnace cannot be reversed before said gas control valve is closed.

3. ln reversing furnace mechanism, the combination of a gas control valve, a gas reversing valve` a purge valve controlled by said reversing valve whereby purging of the furnace of gas is controlled, and means whereby said reversing valve cannot be op` erated before the gas shut-oill valve is in a given position.

4. In reversing furnace mechanism, the combination of a gas shut-off valve, a gas reversing valve, a purge valve controlled by said reversing valve whereby purging of lll) il il the furnace of gas is controlled, and means whereby said reversing valve 'cannot beoperated'before the gas shut-ofi" valveis given a predetermined movement.

5. Inreversing furnace mechanism, the combination of a gas shut-olf valve, a gas reversing valve, a purge valve whereby purging of the furnace is controlled, said purge valve being controlled by said gas shut-off valve andsaid reversing valve, and means whereby the furnace cannot be.- reversed by movement of said gasreversing valve before the gas shut-off valve is given a closing movement.

6. In reversing furnace mechanism, the combination of a gas shut-off valve, a gas reversing valve, a pui'ge valve whereby the purging ofthe furnace of gas is controlled, said purge valve being controlled by a selectively interlocking connection between the gas shut-off valve and the gas reversing valve, and an additional interlock between said gas shut-off valve and gas reversing valvefor causing sameto be operated in a given sequence.

7, In reversing furnace mechanism, the combination of a gas shut-0H valve, a gas reversing valve, a selectively interlocking connection between said valvesy whereb purging of the furnace of gas is controlle and a second interlock between said valves wherebythe same are operated ina given sequence.

8. In reversing furnace mechanism, means for controlling the supply of gas to the furnace, means for reversing the furnace, means controlled by said gas control means and reversing means for controlling the purging of the furnace of combustible gas, and means whereby said gas control means and reversing means cannot function other than in a given sequence.

9. In reversing furnace mechanism, means for controlling the supply of gas to the furnace, means for reversing the operation ot' the furnace, means controlled by the gas control means for controlling the purging of the furnace of heat-generating gas, and means whereby said gas control means and reversing means cannot function other than in a given sequence.

10. In reversing furnace mechanism, gas shut-off valves for controlling the ysupply of combustible gas to opposite ends of the fur nace, gas reversing valves for controlling the course of the gas within the furnace, a purge valve for controlling the purging of the furnace of combustible gas operated in accordance with movements of said gas shut-oitl valves and gas reversing valves, and an interlock between said gas shut-off valves whereby they are operated only in a given sequence.

l1. In reversing furnace mechanism, gas shut-0H valves forcontrolling the supply of conibustible gas to opposite ends of the furnace, gasreversing valves for controlling the course of the gas within the furnace, a purge valve for controlling the purging of the. furnace of combustible gas operated in accordance with movements of said gas shutoff valves and gas reversing valves, and an interlock between said gas shut-off valves and said reversing valves whereby same are operated only in a lgiven sequence.

l2. In reversing furnace mechanism,a gas control valve, gas and air reversing valves, a purge 'valve for controlling the purging of the furnace ofl combustible gas, means whereby the operation of the purge valve is controlled by the operation of one of said other valves, and an interlock between said air and gas reversing valves and said gas control valve.

i3. In reversing furnace mechanism, a gas control valve, gas reversingy valves, a purge valve for controlling thepurging of the furnace of combustible gas, means whereby the operation of the purge valve is controlled by the operation of one of said other valves, and an interlock between said gas reversing valves and said gas control valve.

l-l. In reversing furnace mechanism, a gas shut-oliz valve, a gas reversing valve, an interlock between said valves whereby the purging of the furnace of combustible gas is controlled, and a second interlock between said valves whereby the same are operated in a given sequence.

l5. In reversing furnace mechanism, the combination of a gas control valve, a gas reversing valve, means operatively associated with said valves for controlling the purging of the furnace of combustible gas, and means for limiting the operation of said valves to a given sequence.

16. In reversing furnace mechanism, the combination of a plurality of valves for controlling the liow of gas, means operatively associated with said valves for controlling the purging of the .furnace of a heat-generating gas, and means for limiting -the operation of said valves to a given sequence.

17. In reversing furnace mechanism, the combination of a plurality of valves for controlling the flow of gas, means operatively associated with one of said valves for controlling the purging of the furnace of a heat-generating gas, and means for limiting the operation of said valves to a given sequence.

'18. In reversing furnace mechanism, a plurality of gas shut-off valves, a gas reversing valve, means operatively associated with one of said gas shut-off valves and said gas reversing valve for controlling the purging of the furnace of combustible gas, and means whereby the operation of one of said gas shut-off valves and said reversing valve is limited to a given sequence and whereby the operation of said gas shut-olf valves is limited to a given sequence relative to each other.

19. In reversing furnace mechanism, a gas shut-off valve, a gas reversing valve, a purge valve by means of which the purging of the furnace of combustible gas is controlled, a selectively interlocking connection between said gas shut-off valve and gas reversing valve for controlling said purge valve, and a second interlock between said gas shut-off and gas reversing valve for controlling said purge valve.

20. In reversing furnace mechanism, -a gas shutof valve, a gas reversing valve, a purge valve by means of which the purging of the furnace of combustible gas is controlled, a selectively interlocking connection between said gas shut-off valve and gas reversing valve for controlling said purge valve, and a second interlock between said gas shut-off and gas reversing valve for controlling said purge valve; one of said interlocks under certain conditions causing a movement of said purge valve,'and the other interlock under certain conditions preventing a movement of said purge valve.

21. In reversing furnace mechanism, the combination of a gas shut-off valve for each end of the furnace, a purge valve for each end of the furnace whereby under certain conditions the furnace may be purged of gas from opposite ends thereof, and means for preventing more than one of said gas shutoff valves being opened at a time.

22. In reversing furnace mechanism, the combination of gas supply means for opposite ends of the furnace, means whereby the furnace may be thoroughly purged from opposite ends of the furnace under operating conditions to prevent explosions, and means whereby gas can be supplied to one end only of the furnace at a time.

23. In reversing furnace mechanism, the combination of a gas shut-olf valve, a gas reversing valve, a purge valve whereby the furnace may be purged of combustible gas, and means for preventing the gas reversing valve having its position changed before the gas shut-off valve is closed.

24. In reversing furnace mechanism, the combination of a gas shut-off valve, a gas reversing valve, a purge valve whereby the furnace may be purged of combustible gas, and means for preventing the ,gas reversing valve having its position changed before the position of the gas shut-oif valve is changed in the operating sequence.

25. In reversing furnace mechanism, the combination of means for supplying gas,agas reversing valve, means whereby the furnace may be purged of gas to prevent explosions, and means whereby the reversing valve at the same end of the furnace is prevented from making a reversing movement before the supply of gas at that end of the furnace is shut olf.

26. In reversing furnace mechanism, the combination of means for supplying gas, an air reversing valve, means whereby the furnace may be purged of combustible gas to prevent explosions, and means for preventing the reversal of said air reversing valve before the supply of gas is shut o' at the same end of the furnace.

27. In reversing furnace mechanism, the combination of means for supplying gas, gas and air reversing valves, means whereby the furnace may be purged of combustible gas to prevent explosions, and means wherebysaid gas and air reversing valves cannot be reversed in position before the supply of gas at the same end of the furnace is shut oi.

28. In reversing furnace mechanism, the combination of a gas shut-olf valve, a reversing valve, a purge valve at the same end of the furnace, means whereby under certain conditions said purge valve is controlled by said gas shut-olf valve and said reversing valve, and an interlock between said gas shut-on valve and reversing valve whereby an operation of said valves must be in a given sequence.

Signed at Chicago, Illinois, this 10th day of August, 1920.

CHARLES L. BYRON. 

